The SKS is a Russian semi-automatic carbine, designed in 1945 by Sergei Gavrilovich Simonov. It is formally known as the Samozaryadniy Karabin sistemi Simonova ( Russian: СамозарÑдный карабин ÑиÑтемы Симонова), 1945 (Self-loading Carbine, Simonov's system, 1945), or SKS 45. It was originally planned to serve as the new standard issue weapon for the Soviet military forces, alongside Mikhail Kalashnikov's new AK-47 design, to replace the Mosin-Nagant series of bolt-action rifles and carbines that had been in service since 1891.